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Werk #19201: win_netstat: fix crash on Windows-specific TCP connection states

Component Checks & agents
Title win_netstat: fix crash on Windows-specific TCP connection states
Date May 6, 2026
Level Trivial Change
Class Bug Fix
Compatibility Compatible - no manual interaction needed
Checkmk versions & editions
2.5.0p2
Not yet released
Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

The win_netstat check plugin crashed with a KeyError when parsing TCP connections in the FIN_WAIT_1 or FIN_WAIT_2 state. Windows netstat reports these states with an underscore before the digit (FIN_WAIT_1, FIN_WAIT_2), while the internal ConnectionState enum uses the Linux convention without the underscore (FIN_WAIT1, FIN_WAIT2). The mismatch caused a crash during section parsing. This issue was introduced in Checkmk 2.5.0 when the plugin was migrated from plain string tuples to typed ConnectionState enum values.

Starting with this release, the state name mapping correctly translates the Windows-specific FIN_WAIT_1 and FIN_WAIT_2 values to their enum equivalents, and the plugin also handles the German-locale states SYN_GESENDET and SYN_EMPFANGEN (the German translations of SYN_SENT and SYN_RECV on localized Windows systems).

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